BIOSPECIMEN UNIT ? SUMMARY ABSTRACT The Biospecimen Unit will be responsible for acquiring, processing, archiving, classifying, and distributing (i) bone marrow biopsies, aspirates, and blood samples from patients diagnosed with clonal hematopoiesis of indeterminate potential (CHIP), a pre-neoplastic state at risk of progression to diverse types of myeloid neoplasia and (ii) cutaneous biopsies from patients diagnosed with superficial spreading melanoma precursors (MPs) which are at risk of progression to invasive melanoma. Atlas construction activities will take advantage of ongoing, expanding and well-annotated biospecimen collection activities at the Pasquarello Tissue Bank (Dana Farber Cancer Institute), tissue repositories within the Division of Hematopathology at Brigham and Women?s Hospital (BWH), and tissue repositories of the Division of Dermatopathology at BWH. These repositories are under the direct supervision of PATCH Center members insuring access to the biospecimens necessary for Atlas construction. The Biospecimen Unit has assembled a complementary and well-integrated group of experienced physicians all working at the same Harvard Teaching Hospital and supported by professional staff. These include hematopathologist (Dr. Jon Aster), two dermatopathologists (Drs. George Murphy and Christine Lian), a surgeon (Dr. Charles Yoon), and a clinical oncologist and biobanking expert (Dr. Jerome Ritz), as well as experienced clinical research coordinators. Together, this team will ensure that biospecimens are collected, annotated and shared following a set of established standard operating procedures, Clinical data will be reviewed and harmonized with NCI common data elements and all sampling protocols harmonized with other HTAN Biospecimen Units (as approved by the HTAN Steering Committee and Dana Farber/Harvard Cancer Center IRB). Careful attention will be paid to differences in the design of cross-sectional retrospective Phase I Atlas studies and longitudinal prospective Phase II Atlas studies. Aim 1 will process, characterize, bank, and annotate, in a standardized fashion, viable bone marrow cells obtained from patients with CHIP and myeloid neoplasms, and precursor lesions from patients who have developed or are at high risk of developing melanoma. Existing samples will be used for retrospective studies and newly collected samples (in the case of CHIP, from a patient cohort already accruing) with full control over pre-analytical variables Aim 2 will build a linked archive of CHIP biospecimens from a prospective cohort with serial bone marrow and blood sampling to provide temporal data for Atlas construction. Aim 3 will ensure the distribution of appropriately selected and banked specimens to Center Characterization and Data Analysis Units following pathology re-review by Drs Aster or Murphy and anonymization of patient data. Aim 4 will generate positive and negative tissue and cell-based (FFPE) controls for use by the Characterization Unit in antibody qualification and proficiency testing.